Technical Field
The disclosure relates to flexible transport bags (big bags) for carrying granule, fluid, viscous, or semi-fluid materials.
Description of the Related Art
In the prior art, flexible transport bags (so called big bags) for carrying and stacking of cast materials, powder, liquid, fluid, semi-fluid and other materials are known.
In WO 2013/135520, a large volume packaging container is disclosed for stacking and carrying of thermoplastic materials, in particular bitumen. The container has a bottom panel and a container jacket connected to the bottom panel, wherein the container jacket consists of wall panels. The wall panels are made of flexible material, in particular flat woven fabric or circular woven fabric made of plastic fiber such as polypropylene (PP) or polyethylene (PE) or biodegradable natural fibers. Preferably, there is an inner coating of PP or PE material. The lower half of the container jacket is constricted in the bottom region. Thus, the peripheral expansion of the container in the filled state is minimized. Above the constricted portion, the container expands, and constricts again towards the top of the container. Thanks to this, the cross section of the container is decreased upwardly from the base. By means of this especially waisted shape of the container, the bulge or ridge of the container sides in the lower part of the container height is minimized. However, it has become evident that the expansion of the material inside the bag can lead to balance problems in the upper part of the container. Particularly, the stacking of containers one above the other is hampered by the convergent shape of the container. If such transport bags have to be stacked in confined, box-like spaces such as shipping containers, the bulge in the lower part and the constriction in the upper part of the bags, leads to stability problems.